The present invention relates to a tank type container used for filling and transporting polycarbonate resin pellets, and a method for transporting polycarbonate resin pellets using the container. More particularly, the present invention relates to a tank type container for polycarbonate resin pellets, usable for land or marine transportation of polycarbonate resin pellets, and a method for transporting polycarbonate resin pellets using the container.
In transporting polycarbonate resin pellets in a small volume, there is used a small container having a tetragonal tank 50, such as shown in FIG. 9, or a container having, in place of the tetragonal tank 50, a vertical, compressed drum-shaped tank. In each container, an charging inlet 51 is provided at the top end of the tank, a discharging valve 54 is provided at the bottom end of the tank via a hopper 53, and a supporting frame 55 is provided for stabilizing the tank.
In transporting polycarbonate resin pellets in a large volume, there is used a long, horizontally placed, drum-shaped tank 57 such as shown in FIG. 10, which is fixed directly (with no fitting) to the dumping type bed 58 of a truck or a trailer and is provided as a so-called tank lorry.
The tank 57 has a charging tube 62 for polycarbonate resin pellets at the top of the front end and, at the bottom of the back end, a discharging tube 65 via a hopper 63. The bed 58 can be inclined by the extension of a hydraulic cylinder 59 in such a state that the front is elevated.
In the case of the tetragonal small container of FIG. 9, it is possible to produce only a small-volume container, for the strength required; therefore, a number of containers need to be mounted and transported on a truck or a trailer; this requires much labor in handling and makes low transportation efficiency. Further, to accommodate the hopper 53 and the discharging valve 54, there are required a large space, resulting in low utilization of space.
The small container having a vertical, compressed drum-shaped tank is stronger than the tetragonal container of FIG. 9; however, it can not be produced so as to have a large volume because, even if it is produced in a larger diameter for a larger volume, efficient mounting thereof on the rectangular bed of a truck is difficult. Its production of the tank having a larger height is also difficult in view of the height restriction and safety of the truck or the like.
In the case of a long, drum-shaped tank 57 mounted horizontally on the bed of a tank truck of FIG. 10, it can be produced in a large capacity from the standpoint of the strength and the shape compatibility with the bed 58 of the truck. However, since the tank 57 is permanently fusion-bonded to the bed 58 of the truck, it is usable for land transportation but is not usable for marine transportation.
Further, since the tank 57 is mounted with no fitting, there is a high risk that the tank 57 and the belongings (e.g. a discharging tube 65) provided on the surface thereof collide with external substances and are damaged.
Furthermore, one truck is required for one tank 57, which is low in economical efficiency.
Polycarbonate resin pellets particularly for optical use vibrate and collide with each other by vibration during the transportation, and inevitably generate a fine powder. When such a fine powder is present in polycarbonate resin pellets for optical use to be molded in a certain amount or more, the optical disc molded therefrom has various defects as a recording material, owing to the formation of silver streaks, the generation of carbides, etc.
The objects of the present invention are to provide a tank type container of large capacity which has a sufficient strength, which can be protected from the contact of the belongings with external substances, and which can transport polycarbonate resin pellets by land or by sea efficiently while suppressing the generation of a fine powder; and a method for transporting polycarbonate resin pellets using such a container.
According to the study by the present inventors, the above object of the present invention is achieved by a tank type container for polycarbonate resin pellets, comprising a long, horizontally placed, drum-shaped tank and a parallelopiped container frame surrounding the tank, wherein
the tank is provided with a charging tube at the top of the longitudinal front end, a discharging tube at the bottom of the longitudinal back end, and an air-supplying apparatus for supplying compressed air into the tank, at the outside,
the tank, the charging tube, the discharging tube and the air-supplying apparatus are accommodated in a space surrounded by the container frame,
the container frame is provided, at the bottom corners, with metal fitting members for locking engagable with a locking mechanism possessed by the bed of a trailer, and
the charging tube is projected forward and upward from the tank, the discharging tube is projected backward and upward from the tank, and when the tank is inclined in such a state that the front end is elevated, the charging tube is directed upward and the discharging tube is directed almost horizontally and backward.
The present invention also includes a tank type container according to the above, wherein the air-supplying apparatus comprises air-injecting tubes provided at the front end top of the tank and the back end bottom of the tank, an air-blowing tube connected to a compressed air source, provided at the back of the tank, and tubes for sending air under pressure, provided along the surface of the tank so as to diverge from the air-blowing tube and extend as far as each air-injecting tubes.
The present invention further includes a method for transporting polycarbonate resin pellets using the above tank type container for polycarbonate resin pellets.